An unexpected binding mode for a Pol II CTD peptide phosphorylated at Ser7 in the active site of the CTD phosphatase Ssu72

作者：Xiang Kehui; Manley James L; Tong Liang^*

来源：Genes & Development, 2012, 26(20): 2265-2270.

DOI：10.1101/gad.198853.112

• RNA polymerase
• protein phosphatase
• protein structure

Ssu72, an RNA polymerase II C-terminal domain (CTD) phospho-Ser5 (pSer5) phosphatase, was recently reported to have pSer7 phosphatase activity as well. We report here the crystal structure of a ternary complex of the N-terminal domain of human symplekin, human Ssu72, and a 10-mer pSer7 CTD peptide. Surprisingly, the peptide is bound in the Ssu72 active site with its backbone running in the opposite direction compared with a pSer5 peptide. The pSer7 phosphatase activity of Ssu72 is similar to 4000-fold lower than its pSer5 phosphatase activity toward a peptide substrate, consistent with the structural observations.

• 出版日期2012-10-15